Nitrile Rubber Research Articles

Evaluation of elastomer suitability for CCUS: Chemical compatibility and rapid gas decompression in supercritical CO2

AbstractThe equipment of carbon capture, utilization, and sequestration (CCUS) infrastructure demands a range of elastomers fully compatible with CO2 phases. In this paper, the typical oilfield elastomers, perfluoroelastomer (FFKM), fluoroelastomer (FKM), tetrafluoroethylene propylene elastomer (FEPM), and hydrogenated nitrile butadiene rubber (HNBR), were studied for their chemical compatibility and rapid gas decompression (RGD) in 100% supercritical carbon dioxide (sCO2). At a given test condition, all selected oilfield compounds passed the ISO 23936‐2 acceptance compatibility criteria after 28‐day aging at 100 C and 34.5 MPa in sCO2. After aging, the elongations at break of the FFKM and FEPM compounds increased; tensile strength for FEPM decreased. In contrast to FFKM and FEPM, FKM and HNBR exhibited both lower elongations at break and lower tensile strengths. The moduli of the various elastomers consistently decreased after the sCO2 aging. The RGD testing revealed that all compounds were capable of passing the RGD ISO 23936‐2 criteria. Complementary material analyses by Fourier transform infrared spectroscopy and differential scanning calorimetry along with surface morphology analyses were also conducted to gain additional insight into the suitability of the selected elastomers for sCO2 service.

New elastomeric ceramizable composites based on butadiene-acrylonitrile rubber filled with talc

One of the most serious drawbacks of polymeric materials is their flammability. This poses problems for their use as building materials. The production of elastomeric composites capable of ceramization is one way of making such materials flame-retardant and thus improving their fire safety. Here, we propose the production of ceramizable, highly filled composites based on NBR rubber containing talc and fluxing agent in the composition. The research showed low flammability (88 % reduction in FIGRA), good rheological properties, high mechanical strength of the vulcanizates (tensile strength at break exceeding 7 MPa) and the ability to produce a strong ceramic phase (up to 77 % increase in required destructive force on ceramizable samples). This confirmed the high flame resistance of the composites tested. In the future, similar composites could be considered for the design of cables that supply fire protection systems, escape route lighting or elevators.

Research on classification methods for rubber based on terahertz time-domain spectroscopy with data fusion strategy

Rubber, an essential industrial product, plays a crucial role in industry and human life. However, some manufacturers of rubber use inferior, recycled or low-cost rubber materials to replace high-quality rubber products. Therefore, in order to ensure industrial production, protect natural environment and ensure personal safety, it is of great economic and social significance to enable rapid and non-destructive qualitative identification of rubber products. In this paper, eight different types of black rubber, including Nitrile Butadiene Rubber (NBR), Choloroprene Rubber (CR) and Ethylen Propylen Diene Monomer (EPDM), were selected as research objects. Terahertz Time-Domain Spectroscopy (THz-TDS) technology was utilized to get the absorption spectra, refractive index spectra and time-domain spectra of these samples for exploring the differences between different types of rubber in terahertz spectra. To reduce the data volume, three band selection algorithms were employed to extract features from the absorption spectra and refractive index spectra, and temporal features of time-domain spectra were extracted for subsequent data processing. In the selection of classification model algorithms, K-Nearest Neighbor (KNN), Random Forest (RF) and Supervised Kohonen Neural Networks (S-Kohonen) were employed to recognize these spectral data. To fully exploit the latent information within these data and considering the possibility of the loss of partial information in single-type signal, a feature-level data fusion method was applied to different optical parameter signals to obtain more information about terahertz spectra during the process of data modeling. The results of the research indicated that the model with the highest prediction accuracy was the KNN model, with an accuracy of 97.37%, when refractive index spectra and time-domain spectra were fused as inputs, the F1-score reached 99.64. The performance of data fusion was noticeably better than that of a single-type signal. This study validates the feasibility of using terahertz time-domain spectroscopy for qualitative identification of different types of rubber.

Efficiency of working coveralls and chemical resistant gloves in reducing operator exposure to pesticides

Personal Protective Equipment (PPE) is used to reduce exposure when working with chemicals. For pesticides, exposure scenarios comprise mixing and loading (M&L) and application. The exposure prediction model recommended by European regulatory agencies for operator risk assessments—the Agricultural Operator Exposure Model (AOEM) – is based on 48 operator exposure studies involving over 500 professional operators from 10 European countries in typical working situations to assess exposure under realistic field conditions. We used the AOEM data to assess the efficiency of exposure reduction resulting from wearing chemical-resistant nitrile gloves and non-certified working coveralls during M&L (tank and backpack sprayer), applications using groundboom and airblast spraying, and outdoor and indoor (greenhouse) applications using handheld sprayers. All studies indicated consistent and high exposure reduction > 90% for gloves and non-certified coveralls across all investigated scenarios. Exceptions were almost exclusively observed when an operator incorrectly used the PPE. The mean exposure reduction from all operators, including those that used PPE incorrectly, was 95.0% for gloves and 96.4% for polyester/cotton working coveralls during M&L, and 91.1% for gloves and 94.9% for non-certified coveralls during all application scenarios. This analysis confirms the essential role of PPE and non-certified working coveralls in reducing operator exposure to pesticides. Outliers indicate that operators need to be properly trained and adhere to label instructions to apply pesticides according to good agricultural practices.

Nitrogen-Doped Diamond-like Carbon Buffer Layer Enhances the Mechanical and Tribological Properties of Diamond-like Carbon Films Deposited on Nitrile Rubber Substrate

The poor adhesion between the DLC film and rubber restricts its application of seals. Introducing a suitable interlayer can bolster the adhesion of the coating or film. In this study, nitrogen-doped diamond-like carbon (N-DLC) emerged as the optimal intermediate layer between rubber and DLC. A series of N-DLC/DLC multilayer films were fabricated via DC magnetron sputtering on nitrile rubber (NBR) substrates, varying the substrate bias voltage (0 V, 100 V, 200 V). A scanning electron microscopy analysis revealed that the composite film surface was smoother than the DLC film alone. The results of Raman spectroscopy and X-ray photoelectron spectroscopy indicated a robust bond between nitrogen and carbon atoms in the composite film, with nitrogen facilitating the conversion of sp3C-C bonds into sp2C=C. Mechanical tests demonstrated that the N-DLC interlayer improved film adhesion and reduced the CoF of the composite film to 0.2–0.3. Specifically, the CoF of the N-DLC/DLC film prepared at 100 V was as low as 0.20, with a wear amount of 1.13 mg. Consequently, the inclusion of the N-DLC interlayer substantially enhanced the mechanical and tribological properties of DLC-coated NBR, rendering this coating highly advantageous for various applications.

Biodegradation of Nitrile Gloves as Sole Carbon Source of Pseudomonas aeruginosa in Liquid Culture.

Nitrile gloves have become a significant environmental pollutant after the COVID-19 pandemic due to their single-use design. This study examines the capability of P. aeruginosa to use nitrile gloves as its sole carbon energy source. Biodegradation was determined by P. aeruginosa adapting to increasing nitrile glove concentrations at 1%, 3%, and 5% (w/v). The growth kinetics of P. aeruginosa were evaluated, as well as the polymer weight loss. Topographic changes on the glove surfaces were examined using SEM, and FT-IR was used to evaluate the biodegradation products of the nitrile gloves. Following the establishment of a biofilm on the glove surface, the nitrile toxicity was minimized via biodegradation. The result of the average weight loss of nitrile gloves was 2.25%. FT-IR analysis revealed the presence of aldehydes and aliphatic amines associated with biodegradation. SEM showed P. aeruginosa immersed in the EPS matrix, causing the formation of cracks, scales, protrusions, and the presence of semi-spherical particles. We conclude that P. aeruginosa has the capability to use nitrile gloves as its sole carbon source, even up to 5%, through biofilm formation, demonstrating the potential of P. aeruginosa for the degradation of nitrile gloves.

Metathetic degradation of waste vulcanized emulsion type butadiene-based rubber

Metathetic degradation has been recognized as promising strategy for the treatment of waste vulcanized rubbers as a Waste-to-Resources approach, not only eliminating the pollution but also recycling as resources. However, it was mainly used for the treatment of the waste vulcanized natural rubber, which contains plentiful cis-1,4- structure. Despite of a much higher consumption of the emulsion type butadiene-based rubbers than natural rubber, there was no report on the metathetic degradation of the waste vulcanized emulsion type butadiene-based rubbers due to their less cis-1,4- unit, although the metathetic functionalization of the nonvulcanized emulsion type butadiene-based rubbers have been well reported. Here, the metathetic degradation of waste vulcanized emulsion type butadiene-based rubber was explored with nitrile-butadiene rubber (NBR) glove as a model. Different from the metathetic degradation of waste vulcanized natural rubber via only cross metathesis between cis-1,4-structure and the chain transfer agent (CTA), the ring closing metathesis between the adjacent cis-1,4-structure and 1,2-structure also occurred in the metathetic degradation of waste vulcanized NBR. It is expected to open the door for the Waste-to-Resources approach of all waste vulcanized emulsion type diene-based rubbers.

Insight on the properties of multi-walled carbon nanotubes reinforced nitrile rubber composites cured by ionizing radiation or peroxide: a comparative study

Abstract A comparative study was carried out between ionizing radiation and dicumyl peroxide (Dicup) as two different curing systems for nitrile rubber (NBR) reinforced with different concentrations of multi-walled carbon nanotubes (MWCNTs). Upon ionizing irradiation, the tensile strength (TS) of the composites increases with increasing absorbed dose up to 50 kGy and then decreases with increasing absorbed dose. TS also increases with increasing of MWCNTs content up to 0.75 phr (part per hundred part of rubber). TS values are decreased in the case of Dicup curing as compared with radiation curing. Other characterizations were made, such as the Differential Scanning Calorimeter (DSC), Fourier transform infrared spectroscopies (FTIR), and morphological characterization, which give further implications for the good compatibility between MWCNTs and NBR phases. A study of the effect of fuel on NBR/MWCNTs composites showed that the composites cured by Dicup had lower values for swelling in fuels when compared with others that were cured by radiation.

A low-temperature stretchable XNBR film containing Li-TFSI doped PEDOT:PSS for electromagnetic interference shielding

Stretchable electromagnetic shields have garnered significant attention in the burgeoning field of flexible devices, while traditional strategies developed to maintain adequate electromagnetic shielding performance under large strains are more challenging at low temperatures. Herein, elastic electromagnetic shielding films with segregated conductive network were produced by an extremely simple method of evaporating carboxylated nitrile butadiene rubber latex containing lithium bis(trifloromethanesulfonyl)imide doped poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate). The films of 0.2 mm in thickness are highly stretchable at −20 °C and exhibit an electromagnetic interference shielding efficiency of more than 30 dB at 100 % strain and −10 °C. These properties underscore the potential of the films as effective stretchable EMI shields in low-temperature conditions. Experiments demonstrating the films' ability to block Bluetooth signals from ESP32 chip microcontrollers and electromagnetic waves from Tesla coils further confirm their usefulness, highlighting the practicality of protecting flexible devices in cold environments.

Modification of hydrogenated nitrile rubber with N,N′‐bismaleimide‐4,4′‐diphenylmethane to improve its resistance to heat aging and reduce its compression set

AbstractThis paper delves to improve the upper‐limit temperature of hydrogenated nitrile rubber (HNBR) through regulation of the vulcanization process, filler system and cross‐linking additive. The tensile test and scanning electron microscope images showed that the aging at 180°C significantly accelerated the deterioration in the property of HNBR compared with 150°C aging. The results showed that a higher dosage of bis(1‐(tert‐butylperoxy)‐1‐methylethyl)‐benzene curing agent reduced the compression set of HNBR without sacrificing its tensile strength. Carbon black N539‐filled HNBR exhibited high tensile strength, while carbon black N774‐filled HNBR showed high heat resistance and low compression set. When the HNBR sample was reinforced with 20 phr of N539 and 20 phr of N774 carbon black, it achieved low compression set, high tensile strength, and heat resistance simultaneously. Then, N,N′‐bismaleimide‐4,4′‐diphenylmethane (BMI) was introduced into the HNBR composite as a cross‐linking assistant agent. The residual strength of BMI‐modified HNBR was 20.3 MPa (the retention rate of 92.3%), and its compression set was as low as 19.2% after aging at 180°C for 72 h. Even after aging the composite at 180°C for 168 h, its strength retention rate remained at 83.2% (18.3 MPa). The approach provided here increased the upper‐limit temperature range of HNBR to 180°C.

2-Cyanoethyl dimethyldithiocarbamate, a new contact allergen found in accelerator-free nitrile gloves.

Allergic contact dermatitis (ACD) from rubber glove usage is usually caused by rubber additives such as the accelerators. However, in analyses of the suspected gloves, ordinary rubber allergens are not always found. Accelerator-free rubber gloves are available, but some patients with accelerator allergy do not tolerate them and might also be patch test positive to them. To identify and chemically characterize a new allergen, 2-cyanoethyl dimethyldithiocarbamate (CEDMC), in rubber gloves. We describe two patient cases: patient 1 that led us to the identification of CEDMC and patient 2 with occupational ACD caused by CEDMC. The patients were examined with patch testing including baseline and rubber series, and their own rubber gloves. High-performance liquid chromatography (HPLC) was used for chemical analysis of rubber gloves. The allergen was synthesized and identified by nuclear magnetic resonance, mass spectrometry and infrared spectrometry, and tested on patient 2. CEDMC was identified by HPLC in a nitrile glove associated with hand eczema in patient 1. Patient 2 whose nitrile gloves contained CEDMC was patch test positive to CEDMC. CEDMC is a new contact allergen in nitrile gloves and probably forms during vulcanization from residual monomer acrylonitrile and rubber additives.

Characterization of recycled nitrile butadiene rubber industrial scraps

The amount of rubber scraps derived from rubber goods production consists of about 20–30% of the processed material, so it is necessary to enhance this material by developing new recycling techniques as well as a new market for recycled rubber products. In the present research, nitrile-butadiene rubber (NBR) scraps are reprocessed via a calendering process acting with a mechanical devulcanization. Compounds were prepared with 20%, 80%, and 100% recycled rubber content and characterized. The experimental results highlighted that the compound prepared with 20% recycled rubber content via calendering and compression molding processes shows comparable mechanical properties to that of virgin NBR. The tensile properties are the most penalized by the increasing content of recycled material (100% recycled shows − 25% and − 50% stress and strain at break, respectively). Other properties remain comparable to the standard material up to 80% recycled material: 60 ± 5 Shore A, compression elastic modulus 8 MPa, compression set 20%. FTIR analysis revealed no changes in chemical structure from the recycling process. The results demonstrate that simple mechanical devulcanization can effectively reprocess industrial rubber waste while largely maintaining useful properties. This provides a potential pathway to enhance sustainability in rubber production through the valorization of process scraps.Graphical

Evaluating the Protective Effectiveness of Rubber Glove Materials Against Organic Solvents Upon Repeated Exposure and Decontamination

BackgroundGlove reuse poses risks, as chemicals can persist even after cleaning. Decontamination methods like thermal aeration, recommended by US OSHA, vary in effectiveness. Some studies show promising results, while others emphasize the importance of considering both permeation and tensile strength changes. This research advocates for informed glove reuse, emphasizing optimal thermal aeration temperatures and providing evidence to guide users in maintaining protection efficiency. MethodsThe investigation evaluated Neoprene and Nitrile gloves (22 mils). Permeation tests with toluene and acetone adhered to American Society for Testing Materials (ASTM) F739 standards. Decontamination optimization involved aeration at various temperatures. The experiment proceeded with a maximum of 22 re-exposure cycles. Tensile strength and elongation were assessed following ASTM D 412 protocols. Breakthrough time differences were statistically analyzed using t-test and ANOVA. ResultsAt room temperature, glove residuals decreased, and standardized breakthrough time (SBT)2 was significantly lower than SBT1, indicating reduced protection. Higher temperature decontamination accelerated residual removal, with ΔSBT (SBT2/SBT1) exceeding 100%, signifying restored protection. Tensile tests showed stable neoprene properties postdecontamination. Results underscore thermal aeration's efficacy for gloves reuse, emphasizing temperature's pivotal role. Findings recommend meticulous management strategies, especially post-breakthrough, to uphold glove-protective performance. ConclusionsThermal aeration at 100°C for 1 hour proves effective, restoring protection without compromising glove strength. The study, covering twenty cycles, suggests safe glove reuse with proper decontamination, reducing costs significantly. However, limitations in chemical-glove combinations and exclusive focus on specific gloves caution against broad generalization. The absence of regulatory directives on glove reuse highlight the importance of informed selection and rigorous decontamination validation for workplace safety practices.

Processing-structure-property relationships in practical thin solid-electrolyte separators for all-solid-state batteries

Scalable processing of thin and robust solid-electrolyte (SE) separators is key for the commercialization of high-energy all-solid-state batteries (ASSBs). Herein, we report the preparation of Li6PS5Cl-based thin SE separators incorporating suitable binders for potential use in ASSBs by two scalable wet processing techniques: tape-casting with nitrile-butadiene rubber (NBR) and calendering with carboxylated nitrile butadiene rubber (XNBR). By means of tensile testing and electrochemical impedance spectroscopy, the influence of processing on the mechanical as well as the electrochemical properties of the resulting thin SE separators is investigated. A trade-off between the mechanical and electrochemical properties is observed, which is due to the inextricably linked microstructures (particle size, binder content and distribution, and porosity) induced by the two different processes. Thin SE separators prepared using the tape-casting method with the more well-distributed binder network demonstrate superior tensile mechanical properties compared to the ones prepared by the calendering method. The results provide insights into the processing-structure-property relationships of the thin SE separators, which will contribute to advancing the application of practical thin solid electrolytes in ASSBs.

Experimental and computational analysis of elastomer membranes used in oscillating water column WECs

The study investigates the structural characterisation of flexible membranes used in oscillating water column (OWC) wave energy converters (WECs). Four commonly utilised elastomers – natural rubber, nitrile rubber, silicone, and latex – were subjected to a novel hyperelastic model selection process. A custom bulge test setup enabled the selection of second-order Mooney-Rivlin (SOMR) and Yeoh models for relevant accuracy (RMSE<0.018 MPa), stability and numerical validation. A 1:20 scale OWC model with latex was tested in a water tank to examine the effects of waves with a frequency range of 0.25–1.4 Hz and up to 0.24m amplitude. Water tank experiments demonstrated smooth frequency responses for OWC with membrane, beneficial for consistent power generation. A dry test rig was designed and built to replicate OWC inflation conditions and apply cyclic loadings up to 1.5 Hz, overcoming pressure limitations of the water tank, exploring wider material options, and validating numerical simulation. An optical motion capture system, Qualisys, supported the validation process by providing precise data on membrane deformation during experiments. Furthermore, finite element analysis (FEA) was utilised to conduct stress analysis and parametric studies, assessing the suitability of these materials for flexible OWC application.

Elastomers Based on Nitrile Butadiene Rubber Stabilized with N-Aryl-substituted Camphan-2 and Fenchan-2-amines

Elastomers Based on Nitrile Butadiene Rubber Stabilized with N-Aryl-substituted Camphan-2 and Fenchan-2-amines

Investigation into the state of cure of elastomers through nanoindentation

A novel nanoindentation procedure was developed for measuring the mechanical properties of elastomers as they exhibit surface tackiness. A small dynamic load was superimposed to a larger static deformation after a dwell time for allowing stress relaxation. The outcomes of measurements on a fully crosslinked filled acrylonitrile butadiene rubber (NBR) were analyzed to verify the reliability of this procedure. This method was then employed to investigate the mechanical properties of the same elastomer cured at different temperatures and times by injection molding. As expected, a change from viscoplastic to viscoelastic behavior due to the formation of chemical crosslinks over curing time was found, and mechanical properties plateaus were reached more rapidly at higher manufacturing temperatures. The results were then compared with compression set data: similar trends were detected for the loss factor and the compression set, both decreasing down to a plateau level. Overall, the proposed method demonstrated the ability to recognize undercured regions in elastomer samples - particularly through the determination of the loss factor (tanδ) - and may represent a new tool for improving quality control for the rubber industry.

Steel slag as a low-impact filler in rubber compounds for environmental sustainability

ABSTRACT This study investigates the use of electric arc furnace (EAF) slag, as a substitute for conventional filler, such as calcium carbonate, in nitrile-butadiene rubber (NBR) composites in different volume fraction. The results demonstrate that slag exhibits morphological traits comparable to calcium carbonate when used as a filler, moreover their processability and mechanical properties are similar. Specifically, at 20% v/v, slag-flled NBR exhibits slightly longer scorch times but unchanged vulcanization times. Both fillers at 20% v/v show comparable hardness, compression strength, and elastic modulus. Tensile properties are also comparable, except for the strain at break, where slag-filled NBR shows a 40% higher tensile strain at break. The environmental impact of this innovative slag application has been evaluated through a comparative life cycle assessment. All assessed impact categories demonstrate a reduction of at least 89%. The study suggests that the use of EAF slag has the potential to promote sustainable waste management.

Molecular dynamics investigation on the thermal-oxidative aging and mechanical properties of nitrile butadiene rubber composites with molybdenum disulfide

Molecular dynamics investigation on the thermal-oxidative aging and mechanical properties of nitrile butadiene rubber composites with molybdenum disulfide

Estimating shelf life and degradation mechanisms of nitrile butadiene rubber for viscoelastic dampers

This study investigates the shelf life of nitrile butadiene rubber (NBR) based on age and temperature factors. Natural aging of nitrile butadiene rubber samples is performed under laboratory conditions for 2 years, followed by thermogravimetric analysis to evaluate Arrhenius parameters. Toop’s equation is used to predict shelf life at 5% conversion rate. Model-free kinetic methods, including Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), and Kissinger, estimate shelf life at different temperatures for both virgin and naturally aged nitrile butadiene rubber. Results show close correlation between KAS and Kissinger methods, with slight variations in activation energy impacting shelf life. Fourier-transform infrared spectroscopy (FTIR) tests assess functional group changes with age. Virgin nitrile butadiene rubber activation energy: OFW-73.33 kJ/mol, KAS-68.43 kJ/mol. Aged nitrile butadiene rubber activation energy: OFW-72.57 kJ/mol, KAS-67.88 kJ/mol. Shelf life at 40°C: Virgin nitrile butadiene rubber - OFW-111.29 years, KAS-26.31 years. Aged nitrile butadiene rubber - OFW-89.01 years, KAS-22.37 years. These findings provide valuable insights for predicting and assessing nitrile butadiene rubber viscoelastic damper performance in engineering applications.